Paper manufacturing process
CA 2522242 C · Owner: Strengell, Kimmo · Inventors: Strengell, Kimmo; Ahlgren, Jonni
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a process for manufacturing paper in which a filler , is pretreated and suspended to form an aqueous slurry the aqueous slurry , obtained is combined with an aqueous suspension containing cellulose fibres to form a stock, the stock obtained is treated at least with a cationic retention agent and the treated stock is filtered to form paper. Retention and optical properties are improved by the filler being pre-treated with inorganic colloidal particles having an average size less than 100nm.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed April 14, 2004 and granted July 2, 2013. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 14, 2024.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 14, 2026.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.